Removable inner barrel for air guns



May 17, 1938. w.' R. BENJAMIN ET AL 2,117,935

REMOVABLE INNER BARREL FOR AIR-GUNS Filed April 29, 1957 NR1? m 7 7 51323 1 1172 Patented May 17, 1938 v UNITED STATES PATENT OFFICE Walter R. Benjamin and Theodore S. Benjamin, Granite City, Ill.

Application April 29, 1937, Serial No. 139,811

4 Claims.

This invention relates to air guns and the object of the invention is to provide meanswhereby shot of diiierent diameters may be projected from the same gun, and more particularly to provide an inner barrel or barrels insertible into the original barrel of the gun to reduce the caliber thereof.

Another object is to provide a plurality of inner barrels one nested within the other, whereby the caliber of the gun may be reduced to any extent required or whereby the caliber may be increased by removing one or more of the inner barrels.

A further object is to so form these inner barrels that they may be readily inserted within each other and within the original barrel of the gun and whereby they will frictionally hold a shot in place and provide means whereby each barrel at its outer end is formed to frictionally hold it in contact with an outer barrel.

Our invention is illustrated in the accompanying drawing wherein:

Figure 1 is a longitudinal sectional View through the barrel of an air gun showing a pair of subcaliber barrels disposed within the main barrel of the gun and in section.

Figure 2 is a front elevation of the muzzle end of the gun shown in Figure 1.

Figure 3 is a like view to Figure 1, but showing a single auxiliary barrel inserted within the main barrel of the gun.

Figure 4 is a longitudinal sectional view through a diiferent form of air gun barrel and showing a slightly different construction of the inner barrel.

Referring to the drawing, A designates the outside or false barrel of an air gun and B the orig inal barrel of the gun, C designating the plunger of the gun and D the spring engaging the plunger. We have not attempted to show the full details of an air gun as these details have no bearing upon our invention.

Our invention consists in the use of one or more inner. barrels. We have illustrated in Figure 3 one inner barrel ID. This has an exterior diameter slightly smaller than the original barrel B and a length which is less from breech end to the enlarged portion. The inner barrel may be an inch or more shorter than the outer barrel without any apparent difference in the shooting. The barrel I 0 at its inner end is swaged, as at I I, so as to slightly reduce its interior diameter at the inner end of the barrel l0 for the purpose of frictionally holding a shot within the barrel. The outer end of the barrel is enlarged at l2, this enlargement being gradual so that the barrel in may be forced into the barrel B and will frictionally engage the inner surface of the barrel B at its outer end.

The use of a plurality of interfitting or nested additional barrels is also contemplated by us, and in Figure 1, we have shown two barrels I0 and it one disposed within the other, the barrel m having a reduced or swaged portion H and at its outer end having an enlarged portion I2 This barrel Ill may be inserted within the barrel Hi, and it will be seen that the outer end of the barrel It) frictionally engages the inner face of the barrel in at its outer end and that the barrel Ill terminates short of the inner end of the barrel I8, while the outer end of the barrel H) projects slightly beyond the barrel I0. By having either the barrel ID or the barrel lfi project beyond the original barrel B of the air gun, it is possible to readily remove one or more of these inner barrels so as to adapt the gun to the diiierent sizes of shot. The gun illustrated in Figure 1 can use three different sizes of shot.

While we have shown the outer ends of the barrels l0 and l0 as being expanded in order to frictionally engage with each other and with the barrel B, we wish it understood that they may be enlarged by having the material at the end of the auxiliary barrels exteriorly thickened. Of course, the muzzle end of the auxiliary barrel can be threaded and screwed into the main barrel B or the barrel Ill screwed into the barrel I!) at the muzzle end, but the simplest and most effective way of securing this desired engagement is by forming the barrels at their muzzle ends so as to frictionally engage each other as described. In putting a barrel ID in place, the barrel is inserted in the barrel B and then the end of the auxiliary barrel I0 is tapped just enough to hold the barrel in place. The barrel will protrude from the muzzle end of the barrel B and this makes for easy loading and at the same time permits the barrel It to be withdrawn by the use of pliers, if desired. The same is true of the inner barrel lfl By using this inner barrel, the gun will be safer and shoot truer. The inner barrel will permit the use of small shot which will cost only one-sixth as much as the larger shot and such shot may be used for shooting sparrows but will not break windows or be likely to do other damage. The auxiliary barrel can be adjusted to accord with sights by turning it. The forward end of the barrel l0 or Ill may be notched at l3, so that the auxiliary barrel can be replaced always in the same position after removal. The inner barrel is shorter than the outer barrel B so the plunger will not strike it.

Inasmuch as these inner barrels are shorter than the outer barrel B, these inner barrels or auxiliary barrels are applicable to original or outer barrels of different lengths. By removing the inner barrel or barrels, the air rifle may be used in the ordinary way. It is designed that these inner barrels or auxiliary barrels shall be sold separately and made to fit difierent models and makes of air guns and air pistols now on the market. The owner of an inner barrel or barrels can shoot at least two sizes of shot that lit the barrels, namely, the original air gun shot commonly used in regular'air rifles and smaller shot that fit the inner barrel or barrels.

While we have shown the inner barrels as being held in place frictionally, it is to be understood that other means might be used for this purpose, if desired.

In Figure 4 we have illustrated a slightly different form of barrel A commonly found on the market and an inner barrel W, the outer end of which is flared outward in the form of a cone, as at I2 The inner end of this barrel is tapered at li Of course, it will be understood that the inner barrel may project slightly beyond the outer barrel when the inner barrel is forced home and that there will be a space between the inner end of the inner barrel and the inner end of the bore of the main barrel.

The inner barrels will be made of seamless mandrel-drawn brass and it will be perfectly smooth inside and accurate to the thousandth of an inch.

What is claimed is:

1. In an air gun having a main barrel, an inner barrel insertible into the main barrel through the muzzle thereof and removable from the main barrel, the inner barrel extending beyond the main barrel at the muzzle and having its outer end portion gradually enlarged to frictionally engage the muzzle end of the main barrel.

2. In an air gun having a main barrel, a plurality of inner barrels fitting one within the other, the inner barrels being insertible through the muzzle of the gun, each inner barrel being gradually contracted adjacent its inner end to frictionally engage a shot, the outermost inner barrel terminating short of the inner end of the main barrel and each inner barrel terminating short of the next adjacent outer barrel, all of said inner barrels projecting beyond the main barrel and each inner barrel being gradually enlarged adjacent its outer end to frictionally engage the main barrel and each other.

3. As an article of manufacture, an inner barrel for the main barrel of air guns, the inner barrel being insertible: through the muzzle of the I main barrel of the air gun, the inner barrel having its interior diameter gradually contracted adjacent its rear end and gradually enlarged at its muzzle end whereby it may be'frictionally engaged with the muzzle end of the main barrel.

4. In an air gun having a main barrel, an inner .7 barrel insertible through the muzzle of the main 

